EP1762925B1

EP1762925B1 - Analog input device with integrated pressure sensor and electronic apparatus equipped with said input device.

Info

Publication number: EP1762925B1
Application number: EP05425633.4A
Authority: EP
Inventors: Lorenzo Baldo; Chantal Combi; Dino Faralli
Original assignee: STMicroelectronics SRL
Current assignee: STMicroelectronics SRL
Priority date: 2005-09-09
Filing date: 2005-09-09
Publication date: 2016-12-21
Anticipated expiration: 2025-09-09
Also published as: US7928960B2; EP1762925A1; US20070068779A1

Description

The present invention relates to an analog input device with an integrated pressure sensor, and to an electronic apparatus equipped with said input device, such as, for example, a mobile phone, to which the following description will make explicit reference without this, however, implying any loss of generality.
As is known, latest-generation mobile phones provide a plurality of advanced functions, such as, for example, e-mail management, internet browsing, display of electronic documents, acquisition and display of images, in addition to "standard" functions, such as, for example, management of address books, phone calls, and text messages. Graphic user interfaces (GUIs) enable simple and effective control of the various functions, by means of particular input devices (known as Trackpoint™) arranged in the mobile phones. Such input devices enable input of data and/or commands; for example, they make it possible to scroll lists, make selections, move a cursor displayed on the screen, or, more in general, generate actions within the graphic interface.
Input devices are known which comprise: a control element that can be actuated by a user; a sensor, mechanically coupled to the control element for detecting its actuation and generating corresponding electrical signals; and an electronic detection circuit, which receives and processes said electrical signals in order to determine the datum/command entered by the user and transmit it to an electronic control circuit of the mobile phone, which will generate a corresponding action within the graphic interface (for example, displacement of the cursor, or scrolling of a list).
An analog input device including an integrated pressure sensor of a micro-electromechanical type is described in the European patent application No. 05 425 183.0 , filed in the name of the present applicant on March 31, 2005.
In detail (see Figures 1-2), the pressure sensor, designated by 1, comprises a monolithic body 2 made of semiconductor material (for example, silicon) having a first and a second main outer surfaces 2a, 2b, which are opposite to one another. Sensitive elements 4, in particular of a micro-electromechanical type, and an electronic interface circuit 5, connected to the sensitive elements 4, are formed in the monolithic body 2. The monolithic body 2 has a cross section that is, for example, square, with sides 1 of 5 mm, and its thickness is, for example, 400 µm. Connection pads 6, made of conductive material, are provided on the first main outer surface 2a of the monolithic body 2 for electrical connection of the sensitive elements 4 to the electronic detection circuit (not shown) of the input device. The sensitive elements 4 are arranged in a way corresponding to the directions of actuation of the control element (not illustrated) of the input device; for example, they are arranged to form a cross, in the case where the directions of actuation are four mutually orthogonal (corresponding, for example, to the displacement directions "North", "South", "East", "West" within the graphic interface). Accordingly, each sensitive element 4 preferentially detects actuation of the control element in a corresponding direction, and it supplies a maximum output when the control element is actuated in that direction. The electronic interface circuit 5 is formed in a region of the monolithic body 2 not occupied by sensitive elements 4; for example, it is formed in a central position with respect to the sensitive elements 4.
In detail (see Figure 2), each sensitive element 4 comprises: a buried cavity 8, having sides of, for example, 500 µm, which is arranged, and completely contained and insulated, within the monolithic body 2; a diaphragm 9, which is suspended above the buried cavity 8 and is flexible and deformable in the presence of external stresses; and piezoresistive elements 10, formed in a surface portion of the diaphragm 9. In detail, the piezoresistive elements 10 are formed by diffusion or implantation of dopant atoms and are connected together to form Wheatstone-bridge circuits (one for each sensitive element 4), the outputs of which are connected to the electronic interface circuit 5.
The manufacturing process of the pressure sensor 1 is based upon the process described in the patent application EP-A-1 324 382 for making a SOI wafer, and upon the process described in the European patent application No. 04 425 197.3 , filed in the name of the present applicant on March 19, 2004, for making a pressure sensor.
In brief, in an initial step, a resist mask is formed on top of a wafer of semiconductor material, in particular silicon, comprising a substrate. The mask has areas of an approximately square shape each comprising a plurality of hexagonal mask portions, which define a honeycomb lattice. In particular, the number of areas of the mask corresponds to the number of sensitive elements that it is desired to form, and their arrangement on the wafer corresponds to the desired arrangement of the sensitive elements. Next, using the mask, an anisotropic chemical etching of the substrate is performed, which leads to the formation of trenches, communicating with one another and delimiting a plurality of silicon pillars. In practice, the trenches form an open region with a complex shape (corresponding to the honeycomb lattice of the mask), wherein the pillars extend (having a shape corresponding to the mask portions). Then, the mask is removed and an epitaxial growth is carried out in a de-oxidizing atmosphere (typically, in an atmosphere with high hydrogen concentration, preferably with trichlorosilane - SiHCl₃). Consequently, an epitaxial layer grows on top of the pillars and closes the open region at the top. Next, a step of thermal annealing is carried out, for example, for 30 minutes at 1190°C, preferably in a hydrogen atmosphere, or, alternatively, in a nitrogen atmosphere. As discussed in the aforementioned patent applications, the annealing step causes a migration of the silicon atoms, which tend to move into the position of lower energy. Consequently, and also due to the small distance between the pillars, the silicon atoms migrate completely from the portions of the pillars within the open region so that the buried cavities 8 are formed. Remaining on top of each buried cavity 8 is a thin silicon layer, constituted in part by silicon atoms grown epitaxially and in part by silicon atoms that have migrated, said layer forming the diaphragms 9. At the end of this step, as many diaphragms 9 and as many buried cavities 8 are thus formed, as are the areas of the previously defined mask.
The electronic interface circuit 5 (Figure 2 shows, by way of example, just one bipolar transistor 12) is made using manufacturing steps that are common to the manufacturing process of the sensitive elements 4. In particular, the electronic interface circuit 5 is connected to the outputs of the Wheatstone-bridge circuits formed by the piezoresistive elements 10 of the various sensitive elements 4, and comprises an amplifier stage, including at least an instrumentation amplifier, configured to acquire the output signals of the Wheatstone-bridge circuits, and possibly one or more filtering stages. Conveniently, the electronic interface circuit 5 further comprises an analog-to-digital converter (ADC) stage. In a way not illustrated, electrical insulation regions can be provided for electrically insulating the electronic interface circuit 5 from the sensitive elements 4.
As shown in Figure 3, the input device described in the aforementioned patent application further comprises a package 15, made, for example, of ceramic material, which encloses the pressure sensor 1.
In detail, the pressure sensor 1 is arranged in an internal chamber 16 of the package 15, in particular, it is bonded to a bottom internal surface of the chamber 16 via a layer of adhesive material 17. The internal chamber 16 is filled with a coating gel 18, and is closed at the top by a membrane 19 made of flexible plastic material, which further delimits a main top surface of the package 15. The electrical connection between the pads 6 and the outside of the package 15 is made via metal leads 20, connected to the pads 6, inside the package 15, by means of wires 21. The metal leads 20 are moreover connected to a printed-circuit board (PCB) 22, provided on which are the electronic detection circuit of the input device, and, conveniently, the electronic control circuit of the mobile phone (typically comprising at least one microprocessor circuit).
The membrane 19 and the coating gel 18 constitute an interface between the control element of the input device (for example comprising a set of keys - not shown - arranged on top of the membrane 19) and the sensitive elements 4, and enable transfer of the pressure deriving from actuation of the control element to the diaphragms 9 of the sensitive elements 4. Said pressure brings about a deformation of the diaphragms 9, a variation in the resistivity of the respective piezoresistive elements 10, and, consequently, an unbalancing of the corresponding Wheatstone-bridge circuits, which is detected by the electronic interface circuit 5. In detail, the sensitive element 4 corresponding to the direction of actuation of the control element undergoes a maximum deformation. The electronic detection circuit receives the output signals from the electronic interface circuit 5, detects the information of direction and intensity of actuation, and transmits it to the electronic control circuit of the mobile phone, which generates the corresponding action within the graphic interface. In particular, the direction of the actuation is determined on the basis of the relation existing between the various signals received (in particular, the direction corresponding to the sensitive element 4 that has undergone the largest deformation is determined).
Advantageously, the speed of the action generated within the interface is a function of the intensity of actuation of the control element (i.e., it varies in an analog manner with the intensity of actuation). In fact, the greater the intensity of actuation, the greater the deformation of the diaphragm 9 of the corresponding sensitive element 4, the unbalancing of the Wheatstone bridge, and, consequently, the output signals that are sent to the electronic detection circuit.
The input device described is not, however, optimized in terms of costs and area occupation, in particular as regards assembly of the pressure sensor 1 on the printed circuit board 22. Consequently, the input device is not particularly suited to integration in portable apparatuses, such as mobile phones.
US-A-5 661 245 discloses a force sensor assembly including: a housing body, having a cavity filled with gel; a pressure sensor, mounted at the base of the housing body cavity; a diaphragm, free floating on the gel within the housing body; a solid interface including a plunger; and a retainer, for retaining the solid interface within the assembly. The gel transmits a force exerted on the diaphragm from the solid interface to the pressure sensor, and the pressure sensor outputs an electrical signal corresponding to the force applied to the solid interface. The electrical signal is carried to external processing circuitry via leads extending through the housing body.
EP-A-1 069 419 discloses a pressure sensor including a cylindrical sensor package, a glass base, a sensor chip, and electrode pins. The sensor chip is mounted on the glass base within the sensor package, and the electrode pins, electrically connected to electrodes in the sensor chip, extend through the sensor package for coupling to external processing electronics.
EP-A-1 378 736 discloses an electrical capacitance sensor, in which movable electrodes are formed on a substrate, spaced apart from corresponding fixed electrodes to form capacitive elements. When a detective member is operated, a force is applied to a movable electrode, which is elastically deformed and brought into contact with a corresponding fixed electrode.
The aim of the present invention is consequently to provide an input device wherein a more efficient assembly is provided between a corresponding pressure sensor and a printed circuit board.
According to the present invention an input device and an electronic apparatus are consequently provided, as defined in claims 1 and 16, respectively.
For a better understanding of the present invention, there are now described preferred embodiments thereof, purely by way of non-limiting example and with reference to the attached drawings, wherein:

Figure 1 is a schematic top plan view of a monolithic body of semiconductor material of an integrated pressure sensor belonging to an input device of a known type;
Figure 2 is a cross-sectional view of the monolithic body of Figure 1, taken along the line of section II-II of Figure 1;
Figure 3 is a cross-sectional view of the pressure sensor, with the monolithic body housed in a package;
Figure 4 shows a portable apparatus, in particular a mobile phone, comprising an input device;
Figure 5 is a cross-sectional view of the input device of Figure 4, according to a first embodiment of the present invention;
Figure 6 is a cross-sectional view of the input device of Figure 4, according to a second embodiment of the present invention; and
Figure 7 is a cross-sectional view of the input device of Figure 4, according to a third embodiment of the present invention.

As shown in Figure 4, an electronic apparatus, in particular a mobile phone 25, comprises an outer casing 26, which houses a display screen 27, a plurality of function keys 28, and an input device 30. In a known way, the function keys 28 enable standard functions of the mobile phone 25 to be performed, such as, for example, dialing of phone numbers or entry of text messages, and a graphic interface is displayed on the display screen 27, said interface being made up of a plurality of icons, with a given function (or set of functions) of the mobile phone 25 corresponding to each of the icons. The input device 30 is, for example, arranged in a central portion of the body of the mobile phone 25, in the proximity of the display screen 27, and enables a user to interact with the graphic interface. In particular, the input device 30 enables entry of data and/or commands; for instance, it enables: generation of actions of displacement within the graphic interface and selection and activation of particular mobile phone functions 25, or control of the movement of a cursor (not illustrated) displayed on the display screen 27 in given operating conditions of the mobile phone 25.
In detail (see also Figure 5), the input device 30 comprises: a control element 32, which can be actuated by a user; a pressure sensor 1, mechanically coupled to the control element 32 for detecting its actuation and generating corresponding electrical signals; and a supporting element, in particular a printed circuit board 34, which is connected to the pressure sensor 1 and integrates an electronic detection circuit, configured to receive the aforesaid electrical signals and determine the direction and intensity of actuation of the control element 32. Advantageously, the printed circuit board 34 further integrates an electronic control circuit of the mobile phone 25.
The pressure sensor 1 (shown schematically in Figure 5 and in the subsequent figures) is formed as described with reference to Figures 1-2, so that parts that are similar are designated by the same reference numbers. In particular, the pressure sensor 1 is arranged so as to undergo mechanical deformations due to actuation of the control element 32.
The control element 32 can be operated manually by a user in a plurality of actuation directions, for example, in four directions corresponding to the directions of displacement "North", "South", "East", and "West" (indicated by the arrows), associated to which are corresponding directions of displacement within the graphic interface. In detail, the control element 32 has substantially the shape of a "T" turned upside down, and comprises a base body 32a and an elongated body 32b, joined to the base body 32a. The elongated body 32b extends in a direction perpendicular to the base body 32a and has a tapered shape, ending in an actuation element 35. The base body 32a carries underneath (on the opposite side with respect to the elongated body 32b) a plurality of pressure elements 36. In particular, the pressure elements 36 are rigidly coupled to the base body 32a and have a hemispherical shape. In addition, the number of pressure elements 36 is equal to the number of actuation directions of the control element 32, or, in an equivalent way, to the number of sensitive elements 4.
The printed circuit board 34 is conveniently of the double-face type (i.e. contact metallizations are provided on both of the main faces) and has a first main face 34a and a second main face 34b, opposite to one another and separated by a thickness of, for example, 3 mm. In particular, conductive paths 37, made, for example, of copper, are provided on the first main face 34a.
According to an aspect of the present invention, assembly of the monolithic body 2 to the printed circuit board 34 occurs without interposition of a package.
In detail, according to a first embodiment of the present invention, the printed circuit board 34 has a through opening 39, which traverses the entire thickness of the printed circuit board 34, starting from the first main face 34a as far as the second main face 34b.
The monolithic body 2 is arranged underneath the printed circuit board 34, in such a manner that the first main outer surface 2a faces the first main face 34a of the printed circuit board 34, and the diaphragms 9 of the sensitive elements 4 are set in a position corresponding to, and face, the through opening 39. The second main face 34b of the printed circuit board 34, instead, faces an internal portion of the outer casing 26 of the mobile phone 25. Conductive bumps 38, made with the so-called "screen-printing" technique, are in electrical contact with, and arranged between, the connection pads 6 carried by the first main outer surface 2a and the conductive paths 37, and provide electrical and mechanical connection between the pressure sensor 1, in particular the electronic interface circuit 5, and the electronic detection circuit integrated in the printed circuit board 34. Said connection is made using the so-called "flip-chip" technique, in particular without the use of bonding wires.
A protective material 40 fills, advantageously in a complete way, the through opening 39 and coats the portion of the first main surface 2a facing the through opening 39, and in particular the diaphragms 9. The protective material 40 is an elastomer having a low Young's modulus, for example, a silicone gel, such as Fluorogel™ Q3-6679 produced by the company Dow Corning™, and has the function of protecting the sensitive elements 4 from the outside environment and from the direct pressure exerted by the user, which could cause damage thereto.
The control element 32 is arranged within the through opening 39, in such a manner that the base body 32a and part of the elongated body 32b are embedded in the protective material 40. The pressure elements 36 are each arranged in a position corresponding to, and facing, a respective diaphragm 9. In addition, the actuation element 35 projects out of a window 42 made in the outer casing 26 of the mobile phone 25, so as to be accessible to the user. The protective material 40 has mechanical characteristics such as to keep the control element 32 in a stable resting position, and at the same time such as to enable its displacement following upon actuation by the user. In addition, the protective material 40 has a degree of elasticity so that the control element 32 will assume the resting position again, once actuation has ceased.
During operation, the user displaces the actuation element 35 in one of the actuation directions allowed for the control element 32, causing a corresponding displacement of the base body 32a within the protective material 40. Consequently, one of the pressure elements 36, in particular the one corresponding to the direction of actuation, exerts a pressure on the corresponding diaphragm 9, causing its deformation.
Advantageously, according to an aspect of the present invention (see Figure 6), the monolithic body 2 is housed in a protective region 44, for example, made of resin (commonly referred to as "globe top"). In detail, the monolithic body 2 is fully in contact with the protective region 44 except in the portion of the main outer surface 2a arranged in a position corresponding to the through opening 39 (where it is, instead, in contact with the protective material 40). The protective region 44 has the function of preventing movement of the monolithic body 2 and of protecting it from external stresses.
According to a different embodiment of the present invention (illustrated in Figure 7), through connections 46 are provided through the monolithic body 2, said connections being electrically connected to the connection pads 6 carried by the first main outer surface 2a. The through connections 46 can be made using any known technique, for example, by means of metallized through holes (vias), or using the technique described in EP-A-1 151 962 and EP-A-1 351 288 filed in the name of the present applicant.
In this case, the printed circuit board 34 has a solid and continuous structure (in particular, it does not have the through opening 39), and is arranged in such a manner that the first main face 34a faces the outer casing 26 of the mobile phone 25. The monolithic body 2 is set on top of the first main face 34a, and the conductive bumps 38 are in electrical contact with, and arranged between, the through connections 46 and the conductive paths 37 carried by the first main face 34a.
A containment structure 48, hollow and open at the top and the bottom, for example, having a cylindrical shape and being made of metal or plastic material, is set in contact with the first main face 34a and surrounds the monolithic body 2, so enclosing it. Also in this case, the protective material 40 is provided for coating and protecting the monolithic body 2. The protective material 40 is contained laterally by the containment structure 48, and, advantageously, is at the same level as the top end (i.e., the end opposite to that in contact with the printed circuit board 34) of the containment structure 48.
The control element 32 is arranged, at least partially, within the containment structure 48 so that the base body 32a and part of the elongated body 32b are immersed in the protective material 40 and supported thereby in the resting position. Once again, the actuation element 35 projects from the window 42 made in the outer casing 26 of the mobile phone 25 so as to be accessible to the user.
The advantages of the input device made according to the present invention are clear from the above description.
It is emphasized, however, that the described assembly of the monolithic body 2 of the pressure sensor 1 and of the printed circuit board 34 of the input device 30 involves a smaller thickness and area occupation, and a complexity of fabrication that is considerably lower than that of traditional solutions, thus rendering the input device 30 particularly suited to use in portable electronic apparatuses. In particular, the described assembly does not envisage the use either of a package or of bonding wires, which are notoriously weak as regards mechanical stresses. In fact, it is not necessary to provide a special wiring between the pressure sensor 1 and the electronic detection circuit, in so far as the electrical connection is ensured by the conductive bumps 38. Consequently, the input device 30 has a greater mechanical resistance to failure as compared to traditional devices.
Finally, it is clear that modifications and variations may be made to the input device described and illustrated herein, without thereby departing from the scope of the present invention, as defined in the annexed claims.
The electronic detection circuit can be integrated in the monolithic body 2, together with the electronic interface circuit 5. In this case, in the printed circuit board 34, electrical connections to the electronic control circuit of the mobile phone 25 are in any case provided (as has been said, also said control circuit is conveniently integrated in the printed circuit board 34). In addition, the electronic detection circuit can be integrated in the electronic control circuit of the mobile phone 25.
As will be clear to a person skilled in the art, the shape and structure of the control element 32 may be different. For example, the control element 32 can include keys, or generically pressure areas, arranged on top of a membrane made in the casing 26 of the mobile phone 25 in a position corresponding to the through opening 39, or on top of the containment structure 48. Operation of the keys in this case causes a deformation of the underlying membrane, which is transmitted from the protective material 40 to the diaphragms 9, causing their deformation.
In addition, a different number of sensitive elements 4 may be provided. For example, the pressure sensor 1 could comprise a further sensitive element (for a total of five sensitive elements), which is arranged at the centre of the cross formed by the other sensitive elements 4 and has the function of generating operations of selection, or else of enlargement of an image displayed on the display screen 27. Alternatively, a total of nine sensitive elements 4 may be provided arranged in a regular way in a matrix array of three rows and three columns, in order to be able to generate displacements also diagonally within the graphic interface, and as a whole in the directions: "North" "South" "East" "West" "North-East" "North-West", "South-East", and "South-West".
Each of the sensitive elements 4 could be integrated within a respective semiconductor die, possibly with a corresponding electronic interface circuit. In this case, the various dies could be assembled to the printed circuit board 34 in a way similar to what has been described, using conductive bumps 38 provided between the connection pads of the individual dies and the conductive paths 37.
Furthermore, within the diaphragms 9 of the sensitive elements 4 transduction elements of a capacitive, instead of resistive, type could be formed.
Finally, the described input device can advantageously be used in any portable electronic apparatus equipped with a display screen and a graphic interface to interact with, for example in a portable personal computer, in a PDA, in a videogame console, or in a remote control.

Claims

A data-input device (30) for a user-interface, comprising:
- a control element (32) which can be actuated by a user to input data in said user-interface;

- a pressure sensor (1) mechanically coupled to said control element (32) and provided with a monolithic body (2) of semiconductor material, housing a first sensitive element (4) configured to detect an actuation of said control element (32) ;

- an electronic circuit board (34) electrically connected to said monolithic body (2) and including an active electronic circuit operatively coupled to said pressure sensor (1) to perform data-input operation in said user-interface based on electrical signals outputted from said first sensitive element (4), said monolithic body (2) having electrical-contact areas (6) carried by a first main surface (2a) thereof, and said electronic circuit board (34) having conductive regions (37) carried by a main face (34a) thereof; and

- connection elements (38) for mechanical and electrical connection of said monolithic body (2) to said electronic circuit board (34),
characterized in that said connection elements (38) include conductive bumps (38) which electrically connect said electrical-contact areas (6) of said monolithic body (2) to said conductive regions (37) of said electronic circuit board (34) without interposition of a package, in order to allow electrical connection of said active electronic circuit to said first sensitive element (4).
The device according to claim 1, wherein said first main surface (2a) is at least partially in contact with a protective material (40), configured to transmit a pressure deriving from actuation of said control element (32) to said first sensitive element (4); said protective material (40) being an elastomeric material, in particular a silicone gel.
The device according to claim 2, wherein said control element (32) is embedded at least partially in said protective material (40) and includes at least a pressure element (36) arranged in a position facing said first sensitive element (4); said pressure element (36) being configured to exert pressure on said sensitive element (4) following upon actuation of said control element (32).
The device according to any one of the preceding claims, wherein said conductive bumps (38) are arranged in direct contact between said electrical-contact areas (6) and said conductive regions (37).
The device according to claim 4, wherein said electronic circuit board (34) has a through opening (39), and said first main surface (2a) of said monolithic body (2) is arranged at least partially in a position corresponding to, and facing, said through opening (39); said through opening (39) containing said protective material (40).
The device according to claim 4 or 5, wherein said monolithic body (2) is housed in a protective region (44), in particular of the globe-top type.
The device according to any one of claims 1-3, wherein said monolithic body (2) further has through connections (46) connected to said electrical-contact areas (6) and traversing said monolithic body (2) as far as a second main surface (2b) thereof, opposite to said first main surface (2a); said conductive bumps (38) being arranged in direct contact between said through connections (46), at said second main surface (2b), and said conductive regions (37).
The device according to claim 7, further comprising a containment structure (48), set in contact with said main face (34a), surrounding said monolithic body (2), and containing said protective material (40).
The device according to any one of the preceding claims, wherein said first sensitive element (4) comprises: a cavity (8) contained and insulated within said monolithic body (2); a diaphragm (9) formed in a surface portion of said monolithic body (2) and suspended above said cavity (8); and transduction elements (10) configured to detect deformations of said diaphragm (9) following upon actuation of said control element (32).
The device according to any one of the preceding claims, wherein said monolithic body (2) houses further sensitive elements (4); said control element (32) being actuatable along a number of actuation directions and each of said first sensitive element and further sensitive elements (4) being arranged along a corresponding one of said actuation directions, so that actuation of said control element (32) along a given one of said actuation directions causes a maximum output from a corresponding one of said sensitive elements (4).
A process for manufacturing a data-input device (30) for a user-interface provided with a control element (32) which can be actuated by a user to input data in said user-interface and with an electronic circuit board (34), comprising:
- forming in a monolithic body (2) of semiconductor material a first sensitive element (4) configured to detect an actuation of said control element (32), and electrical-contact areas (6) carried by a first main surface (2a) thereof;

- mechanically coupling said monolithic body (2) to said control element (32) ;

- forming in said electronic circuit board (34) an active electronic circuit, operatively coupled to said pressure sensor (1) to perform data-input operation in said user-interface based on electrical signals outputted from said first sensitive element (4), and conductive regions (37) carried by a main face (34a) thereof; and

- electrically and mechanically connecting said monolithic body (2) to said electronic circuit board (34),
characterized in that connecting said monolithic body (2) to said supporting element (34) comprises electrically connecting said electrical-contact areas (6) of said monolithic body (2) to said conductive regions (37) of said electronic circuit board (34), without interposition of a package and by means of conductive bumps (38), in order to allow electrical connection of said active electronic circuit to said first sensitive element (4).
The process according to claim 11, wherein mechanical coupling comprises: arranging said first main surface (2a) at least partially in contact with a protective material (40), in particular an elastomeric material, configured to transmit a pressure deriving from actuation of said control element (32) to said first sensitive element (4); and arranging said control element (32) at least partially within said protective material (40) in a position facing said first sensitive element (4), said control element (32) carrying at least one pressure element (36) configured to exert pressure on said sensitive element (4) following upon actuation of said control element (32).
The process according to claim 11 or 12, wherein connecting said monolithic body (2) to said electronic circuit board (34) comprises arranging in direct contact said conductive bumps (38) between said electrical-contact areas (6) and said conductive regions (37).
The process according to claim 11 or 12, wherein connecting said monolithic body (2) to said electronic circuit board (34) further comprises:
- forming through connections (46), which are connected to said electrical-contact areas (6) and traverse said monolithic body (2) as far as a second main surface (2b) thereof, opposite to said first main surface (2a); and

- arranging in contact said conductive bumps (38) between said through connections (46), at said second main surface (2b), and said conductive regions (37).
The process according to any one of claims 11-14, wherein forming a first sensitive element (4) comprises: forming a cavity (8) contained and insulated within said monolithic body (2); forming a diaphragm (9) in a surface portion of said monolithic body (2) suspended above said cavity (8); and forming transduction elements (10), which detect deformations of said diaphragm (9) following upon actuation of said control element (32).
An electronic apparatus (25) comprising a display device (27), a user-interface, a data-input device (30) operable by a user to input data in said user interface, and an electronic circuit board (34) including an active electronic circuit configured to control data-input operation in said user-interface and operation of said electronic apparatus (25), characterized by said data-input device (30) being according to any one of claims 1-10.
The apparatus according to claim 16, chosen in the group comprising mobile phones, PDAs, personal computers, videogame consoles, and remote controls.